For ESR studies of molecular rotation in liquids it is desirable to match the spin probe as closely as possible to the solvent molecules. In the work reported here the solvent is a model lubricant whose internal and overall motions have been characterized from carbon-13 NMR relaxation measurements. We are attempting to develop new compounds for use as low- and high-traction fluids: this is particularly important for the latter since suitable liquids are not found in nature. Previously, we have examined model lubricants which have the approximate shapes of a bent cylinder and a sphere, namely di-n-octylether and dicyclobexylmethylpentane (DCMP). In the present work we have chosen a cylindrical molecule, n-octylnaphthalene, and a possible sphere, dicyclohexyl-3,4-furun dicarboxylate - these compounds represent low- and high-traction fluids respectively. For these two compounds we have been able to prepare two spin probes which match their sizes and shapes very closely. They are respecti vely, 5-(n-octyl)-1,1,3,3-tetrakis(trid cutleriomethyl)-isoindolin-2-yloxyl (OTMIOD) and 1,3,2-dithiazol-2-yl dicy clohexyl ester (BCCD). Ideally, the probes should not have any unresolved hyperfine structure hence methyl-group deuteration was necessary to minimize the line widths for OTMIOD; the BCCD radical has no unresolved hyperfines. ESR measurements were made on OTMIOD at both X- and W-bands and it has been shown that the overall motion is anisotropic - the slower of the two motions corresponds to the value of the overall motion determined from the NMR relaxation measurements. A similar result was obtained for the BCCD spin probe studied at X-band only. Activation energies have been estimated for the overall motions from both the ESR and the NMR experiments. Viscosities and the associated temperature coefficients were measured for the two model lubricants using an ESR method.